[Ocfs2-devel] [PATCH] ocfs2: send SIGXFSZ if new filesize exceeds limit

[Wengang Wang]

On 10-02-25 21:55, Joel Becker wrote:
> On Fri, Feb 26, 2010 at 10:18:13AM +0800, Wengang Wang wrote:
> > On 10-02-25 12:01, Joel Becker wrote:
> > > On Fri, Feb 26, 2010 at 12:29:19AM +0800, Wengang Wang wrote:
> > > > Yes that I considered using inode_newsize_ok().
> > > > I'am not sure if checking i_size is safe(lack of knowledge).
> > > 
> > > 	It should be, given that i_mutex is held.  Filesystems that
> > > don't handle their own setattr get to inode_newsize_ok() via
> > > vmtruncate.
> > 
> > What if this case:
> > 0) there is a file with size 4k.
> > 1) user sets file max size to 1k.
> > 2) user resize the 4k-size file to 2k.
> > 
> > If we go with inode_newsize_ok(), the operation succeeds. But doesn't it
> > disobey the file size limit?
> > I didn't find a explicit description for that case. But I prefer that
> > step 2) fails.
> 
> 	It was already larger.  You haven't broken anything.  I don't
> know exactly what POSIX says, but since inode_newsize_ok() is the
> behavior used by most or all other Linux filesystems, we should be
> consistent unless we're sure POSIX disagrees.
> 	Wikipedia states that SIGXFSZ is only triggered when a process
> causes a file to *grow* past the limit.  It doesn't mention shrinking.
> Use inode_newsize_ok().

Ok.
I will post the revised patch later.